Water purification



Oct. 10, 1933. M. BRANDT HATER PURIFICATION a1 Filed larch 29 2Sheets-Sheet 1 ngm Oct. 10, 1933.

M. BRANDT WATER PURIFICATION Original Filed March 29, 1926 2Sheets-Sheet '2 flzllardfirandi,

Rested Oct. 10, 1933 UNITED STATES PAFEN oar-ion Original no. 1,181,314,ems November 11, 19:0,

Serial No. 98,385,1Iarch 29, 1926.

for reissue 633,007

Application September 13, 1932. Serial No.

5 Claims. (01 210-82)- My invention relates to the art of pin-usingwater, and it has particular reference to a method of and apparatus forpurifying water with the aid of activated carbon. 7

Water purification, or the removal from natural waters of variousimpurities harmful to health, is now recognized as a civic necessity. Inmany instances, purification is effected by filtering the water througha bed of sand, by treating with chlorine, or like methods. It has alsobeen proposed to purify water by means of activated carbonaceousmaterial, but such proposals, while particularly desirable, have notbeen received with favor, due to the mechanical diflicultiesencountered.

It is the object of this invention to provide means for the purificationof water with activated carbon in a metal container without theattendant disadvantages which heretofore prevented the successfulaccomplishment of such an operation.

This object is realized by filtering water through a bed of activatedcarbon, which, it has been found by exhaustive experiments andobservations, is highly efiective in removing color, odor, taste,bacteria, and other impurities from water which render it unfit, in itsnatural condition, for domestic or industrial use. v It is much moreeffective for this purpose than anyother form of carbon. Such carbon,however, being a good conductor of electricity and electr'o-negative tomost metals, in the presence of water forms a galvanic couple withmetals, developing electric currents which cause rapid corrosionordisintegration of metals and untimely failure of the installation. Toovercome this difilculty, I maintain the carbon out of contact with themetal walls of the container and preferably space the filtering bed ofactivated carbon from accessory metal elements by means ofsomethingother than metal. This removes the major difiiculty which has heretoforeprevented the exploitation of filters oi this character.

I find it best to use as a purifying material firm coarse grains ofactivated carbon about 85 per cent of which will be retained on a 100mesh sieve, Bureau of Standards specifications. Other grain sizes may beemployed, if desired, but the specification given provides a filteringmaterial through which water may rapidly percolate,

while, however, contacting for a sufiicient time and with sufiicientcontact area to insure the proper removal of impurities. As stated, thisbed of carbon in the present invention dam not contact with the metalwalls of the container or with accessory metal eleme'nts'to'causegalvanic actions. To relieve the purifying material from extra duty, Iusually provide beds 7 of filtering sand at opposite sides, which notonly remove some dirt, color, etc., but also facilitate the SD80? ing ofthe activated carbon in practical installations.

Aacompared with other forms of amorphous carbon, activated carboniis agood conductor for the electrical current. iMost commercial activatedcarbons are excellent conductors. Those coarse grades of activatedcarbon which I have so far prepared for the present apparatus share thisproperty. Where the activated carbon is charged directlyinto a metalcontainer composed of, for example, iron or steel, and water is passedthrough the carbon, the metal container is rapidly disintegrated. Also,the activated carbon is contaminated, probably with oxidation productsof the metal container, and the special activity of the carbon for thepurpose of purifying water is'materially lessened. In addition to thecontamination of the carbon, it is possible that the 1 loss of activityis at least in part-due to the removal of adsorbed oxygen. Apparentlywhere the carbon is in conductive relation to the metal walls of thecontainer, hydrogen is evolved by reason of an electrolytic reaction andacts as a depolarizer keeping the carbon stripped of adsorbed oxygen.Even in the case of filtration of non-oxygen-containing aqueous liquids,such as deep well water through activated carbon contained in a metalfilter, disintegration of the metal container and contamination of thewater occur. In addition to these disadvantages, if the metal containeris not separated fromthe carbon by an insulating material, the filtrateis contaminated in'aninidesirable manner.

In accordance with my inventionthe activated carbon is maintainedisolated or separated from metallic conductors with which it can form a.galvanic couple. Incommercial use metallic containers are highlyadvantageous, due to their resistance to the pressure under which thefilter is desirably operated. The iron or steel or other metalliccontainers which are used in accordance with my invention are interiorlyinsulated with a water-proof, permanent dielectric, such as rubber,bakelite or other phenol condensation products, or a good grade ofenamel.

In the accompanying drawings. illustrating typical installations offilter apparatus incorporating the principles of my invention, 7

Fig. 1 shows in elevation what may be termed a bucket type filter; Fig.2 is a vertical section of the filter shown in Fig. 1;

' Fig. 3 is a broken away view of the bottom of the filter shown in Fig.1;

Fig. 4 is a vertical section of a pressure type filter made of metal; a

Fig. 5 is a top plan view, partly in section, of the filter shown inFig. '4; and

Fig. 6 isa fragmentary view, partly in section, showing in detailthelower portion of the filter shown in Fig. 4 and taking it-at rightangles to the view in Fig. 4.

In the constructionillustrated in Figs. 1, 2 and 3, the container fortheactivated carbon is a metal bucket or pail-like structure 1, whichmay be of either enameled iron or other type of metal bucket having alining or coating 1 of an insulating material such as bakelite, rubberor enamel. In a modification which has proven satisfactory in practice,ordinary enameled iron is employed as the container. The bucket orcontainer 1 is open at its top and depends upon gravity for percolationof the water through the filter medium. At the base of the container isa perforated supporting means or false bottom 2 which acts to supportthe filter bed above the bottom 3. The bottom is provided with a valvedoutlet 4 through which the filtrate is drawn for consumption. Within thecontainer and positioned on the perforated supporting means 2 is abottom layer 5 of sand. Above the sand is provided a layer or strata 8of coarse grain activated carbon. It willbe seen that the carboncompletely fills a horizontal section of the container, the insulatingcoating 1 determining the peripheral limits of the activated carbon bedand separating the same from the metal walls of the container. An upperlayer 7 of sand is positioned above the bed of carbon and is maintainedin position by a perforated diaphragm 8 of any convenient material. Asthe sand layers 5 and I insulate the activated carbon bed from thesupport 2 and the perforated diaphragm 8, re-

. spectively, the nature of these latter elements is immaterial forpresentpurposes. The structure isprovidedwithabailQandasupportingframwork 10. I

The modification shown in Figs. 1, 2 and 3 is intended for field andhousehold use where a large volume and rapid rate of fioware notessential factors. In Figs. 4, 5 and Bis illustrated a filter apparatusof larger type which is adapted for use in connection with a pressuresystem. This latter modification comprises a cylindrical container whichis preferably made of iron, steel or other metal which will withstandthe pressure of the.

water. The inner side of the metal container,

is coated or lined with a layer 26 of bakelite, hard rubber or othermaterial withstanding long contact with water and of insulatingproperties. Within the container 25 is a perforated supporting member'orfalse bottom 2'7; below which is a water chamber 28 and an outletconduit 29. The metal container screws into a bottom casting 30 whichserves as a support for the whole apparatus. Above the.peri'oratedsupport 27 is a layer of sand or gravel 31. An upper layer 33 of sand isplaced above the activated'carbon bed and if desirable held in place byan upper perforated diaphragm or grating 34. A water chamber 35 isprovided above the grating 35. A flange 36 is screwed to the top of themetal container and a cover 37 is secured to the flange by means ofsuitable bolts or other fastening devices. Water is introduced into thefilter from the pressure line 38 which communicates with the top 37.

'The activated carbon completely fills a relatively deep horizontalstrata within the metal container and forms a pervious bed which con--,stltutes the path of how for water passing through The lining 26 ofinsulating material 1 forms. the peripheral limits of the activatedcarthe filter.

carbon and the aqueous medium, whatever be the nature of the chemicalreaction involved in such disintegration, is prevented and the containeris suitable for almost unlimited service in supporting the activatedcarbon.

The various modifications coming within the spirit of my invention areintended to be included in the appended claims.

I claim:

1. In an apparatus for the purification of water with activated carbon,a metal container, a pervious bed of electrically conductive activatedcarbon disposed in said metal container, and an electrically insulatingmaterial in said metal container and separating said bed of activatedcarbon from said metal container, thereby preventing the activatedcarbon from forming a galvanic couple with the metal of the container,whereby disintegration of the metal container, and contamination of theactivated carbon and water are prevented.

2. In an apparatus for the purification of water with activatedcarbon,sa metal container, a

pervious bed of electrically conductive, oxygenadsorbing activatedcarbon disposed in said container, and an electrically insulatingmateniu in said metal container and separating said bed of activatedcarbon from said metal container, thereby preventing the carbon fromforming a galvanic couple with oxidizable metals when the apparatus isin use and thus to make oxygen ad- I sorbed by the carbon available forreaction with impurities in the water.

3. In an apparatus for the purification-oi water, a metal containerhaving a coating of an tact with the metal container,la perforatedsupporting means for said bed, and a layer oi sand between saidsupporting means and said bed of activated carbon. I

5. In an apparatus for the purification of water, a metal containerhaving inlet and outlet conduits communicating therewith, a pervious bedof activated carbon in said container and forming the path oi flow forthe water passing

